All political parties should reflect on a vision for the kind of society they wish to see in the coming decades, the historian Prof Gearóid Ó Tuathaigh said during the opening address of the Merriman

Speaking on the topic In Time of Change: Ireland 1968-2007, Prof Ó Tuathaigh of NUI Galway said the Irish were no longer "the plucky victims of history, playing catch-up in living standards with our long-powerful neighbours".

"The challenge of achieving a satisfactory level of social cohesion, of getting an acceptable balance between, on the one hand, shared values and civic harmony and, on the other, forms of cultural pluralism that enrich the shared life of the nation rather than endanger its cohesiveness, that challenge is upon us, and it is urgent," he said.

The 40th Merriman Summer School runs in the north Clare spa town until Saturday. It commemorates the 18th century Clare poet Brian Merriman, whose noted work is the 1,026-line poem, Cúirt An Mheán Oíche.This week a series of lectures, seminars and symposiums are being held on the theme of Changed Utterly? Ireland 1967-2007, interspersed with cultural events and céilithe.

Prof Ó Tuathaigh paid tribute to the summer school, saying that it had a creative and mischievous capacity for regular re-invention.

He said the aftermath of a general election was a time when all parties take stock, but their reflection and analysis should "go beyond the assessment of electoral fortunes".

"With the retirement of an incumbent Taoiseach already on the horizon, there is a particular opportunity for and onus on the largest ruling party, Fianna Fáil, to engage energetically and publicly in this debate on the future shape - the values and vision issues, as well as the economic management - of Irish society."

He suggested that the ridicule that followed Éamon de Valera's 1943 speech and others detailing a vision for the State had scared off most of his successors from espousing a social vision.

"The time has come for the political leadership to articulate a more coherent and inspiring vision of the kind of Irish society they envisage for the next generation," Prof Ó Tuathaigh said.

Over the past 40 years there had been immense changes characterised by the European "odyssey", the transformation in the North, the liberation of women and globalisation.

Ireland was massively more urbanised, with the tilt of development towards the eastern half of the country.

The Aer Lingus decision to move Heathrow slots from Shannon to Belfast was the latest manifestation of a failure of regional planning which, along with crime, health and housing, was suffering from confused, inconsistent strategies.

Ireland was now a host society for immigrants. It would have been unimaginable that 30 per cent of the population of Gort in Co Galway would be Brazilian.

"We need to have our own serious debate - informed by the particularity of our own historical and current circumstances - on what version of multiculturalism is likely to serve Irish society best in the years ahead."